Xcode 9 Release Notes says that Swift 3 compilation is supported:
One compiler for Swift 4 and Swift 3, Swift 4 and Swift 3 targets can be compiled together in the same project.
I have installed Xcode 9 beta.
But when I press Build it shows bunch of errors. Are some special preparations need to do when use Swift 3 in Xcode 9?
UPD:
Module compiled with Swift 3.1 cannot be imported in Swift 4.0
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